CN1058863A - Rotor of motor having no brush and manufacture method thereof - Google Patents

Abstract

The present invention relates to a brushless motor rotor with permanent magnets. A yoke iron is formed by laminating a plurality of silicon steel sheets, so that the outer circumference of the yoke iron includes an even number of at least 4 magnetic poles. Among these magnetic poles, every other magnetic pole is approximately Equal distances are provided to arrange the grooves with permanent magnets for the magnetic field, so that the permanent magnets for the magnetic field with the same magnetic field on the side facing the rotating shaft are arranged in the grooves to constitute the rotor of the brushless motor of the present invention, thereby achieving a small size. And high efficiency, and the permanent magnet will not be damaged or scattered during high-speed rotation.

Description

This invention relates to high efficiency brushless motors suitable for high speed rotation, and more particularly to their rotors.

A brief description of the attached drawings

Fig. 1 is the longitudinal sectional view of the brushless motor adopting the permanent magnet rotor of the present invention;

Figure 2 is a perspective view of the rotor;

Figure 3 is a front view of the silicon steel sheet;

Fig. 4 is a diagram schematically showing the magnetic force lines of the permanent magnet rotor inside the brushless motor;

Fig. 5 shows the second embodiment of the present invention, the front view of the permanent magnet rotor when changing the pole width;

Fig. 6 is the front view of the third embodiment rotor with slits on the magnetic poles;

Fig. 7 is a diagram schematically showing the internal magnetic force lines of the brushless motor with the permanent magnet rotor of the third embodiment having slits on the magnetic poles;

Fig. 8 shows the 4th embodiment of the present invention, has the front view of permanent magnet rotor with 6 magnetic poles;

Fig. 9 is an enlarged cross-sectional view showing the bridging portion of the permanent magnet rotor of the fifth embodiment of the present invention;

Fig. 10 is the plan view of the silicon steel sheet of the 6th embodiment of the present invention;

Fig. 11 is a diagram showing the flow direction of magnetic lines of force when a load torque acts according to the magnetic field analysis;

Fig. 12 is a three-dimensional exploded view of the permanent magnet rotor of the seventh embodiment of the present invention;

Fig. 13 is a sectional view of the assembled rotor shown in Fig. 12;

Fig. 14 is a diagram showing the flow of magnetic lines of force when forming a magnetic circuit;

Fig. 15 is an axial sectional view of a brushless motor with a permanent magnet rotor according to the first embodiment of the present invention;

Fig. 16 is a perspective view showing a permanent magnet rotor according to an eighth embodiment of the present invention;

Fig. 17 is an axial sectional view showing a brushless motor adopting the permanent magnet rotor of the eighth embodiment;

Fig. 18 is an exploded perspective view showing a permanent magnet rotor according to a ninth embodiment of the present invention;

Fig. 19 is a sectional view perpendicular to the axis of rotation of the permanent magnet rotor of the ninth embodiment;

Fig. 20 is a cross-sectional view perpendicularly intersecting with the yoke rotating shaft showing a part of the 9th embodiment yoke;

Fig. 21 is a sectional view vertically intersecting with a part of the yoke iron of another example of the ninth embodiment shown in enlarged form;

Fig. 22 is an enlarged axial sectional view of a permanent magnet rotor according to a tenth embodiment of the present invention;

Fig. 23 is a perspective view showing the permanent magnet rotor of the eleventh embodiment of the present invention;

Fig. 24 is a perspective view of a permanent magnet rotor showing another example of the above-mentioned embodiment;

Fig. 25 is the front view of the rotor shown by cutting off the rotary shaft of the above embodiment;

Fig. 26 is a perspective view showing a permanent magnet rotor according to the present embodiment;

Fig. 27 is a perspective view of a permanent magnet rotor that is twisted;

Fig. 28 is a longitudinal sectional view of a conventional example of a brushless motor

Fig. 29 is a perspective view of a conventional example of a rotor;

Fig. 30 is a perspective view showing a conventional example of a rotor having a guard member.

Generally speaking, in a brushless motor, a permanent magnet made of ferrite or the like is provided on the outer surface of a cylindrical rotor.

For example, as shown in FIG. 28, a conventional brushless motor 1 has a motor case (stator) 2. This motor case 2 has a cylindrical side wall 3, and a front panel 4 and a rear panel 5 that close both ends of the side wall. . Inside the side wall 3, a plurality of exciting coils 6 arranged in a cylindrical shape are fixed to the wall surface. A concentric rotary shaft 8 is fixedly formed at the center of the rotor 7 . The rotary shaft 8 protrudes from both ends of the rotor 7, and one end is freely supported by the bearing 10 installed in the hole 9 of the rear panel 5 of the motor body 2, and is supported by the front panel 4 installed on the motor housing 2. The bearing 12 in the hole 11 makes the other end of the rotary shaft 8 freely rotatable and supported. On the inner side of the side wall 3 of the motor body 2 is provided an annular magnetic pole sensor support member 13 on which a plurality of magnetic pole sensors 14 are held fixed so as to be located near the surface of the rotor 7 .

FIG. 29 shows a conventional rotor 7 . The rotor 7 is constructed so that the rotary shaft 8 is inserted into a cylindrical yoke 70, and the rotary shaft 8 and the yoke 70 are integrally formed. A pair of arc-shaped magnetized permanent magnets 71 constituting N poles on the outside and S poles on the inside and a pair of arc-shaped magnetized permanent magnets 72 constituting S poles on the outside and N poles on the inside are attached to the yoke in a cross shape 70 on the peripheral surface.

In this brushless motor 1, the magnetic pole position of the rotor 7 is detected by the above-mentioned magnetic pole sensor 14, a current is passed through the corresponding exciting coil 6 by a control circuit not shown, and the rotor is rotated by the interaction between the current and the magnetic force lines. The magnetic pole position of the rotating rotor 7 is detected again by the magnetic pole sensor 14. The above-mentioned control circuit supplies current to different exciting coils 6, and the rotor 7 is driven to rotate again. By repeating the above operation, the rotor 7 is continuously rotated, and this rotational force is taken out to the outside of the motor through the rotary shaft 8 as power.

In addition, since the centrifugal force of the permanent magnets 71 and 72 attached to the rotor 7 increases in the brushless motor 1, as shown in FIG. , 72 of the protective member 73, and the protective member 73 is used to prevent the permanent magnets 71, 72 from flying away due to the centrifugal force accompanying the high-speed rotation.

However, in brushless motors using ferrite magnets, since the maximum energy product is 3.3MGOe and the residual magnetic force line density is as small as 3.8KG, in order to generate sufficient torque for driving the motor, it is necessary to increase the permeability of the magnetic circuit Therefore, it is necessary to use more magnets, so there is an inappropriate situation that causes the size of the motor to increase.

In addition, in the case of a scroll compressor used for high-speed rotation, when the stress caused by the centrifugal force accompanying high-speed rotation is greater than the material strength of the permanent magnet or the fixing force of the magnet to the rotor, permanent magnet damage may occur. damage or permanent magnet flying.

Furthermore, when covering the rotor with a protective member in order to prevent the permanent magnet from flying, not only the manufacturing process of the rotor is complicated, but also the gap between the rotor and the definition is increased by the thickness of the actual protective member. As a result, the magnetic resistance increases and the magnetic Density becomes reduced, thereby reducing efficiency.

The present invention is in view of the above-mentioned problems existing in conventional brushless motors, and aims to effectively solve these problems.

Therefore, an object of the present invention is to provide a rotor for a brushless motor that can be compactly configured with high efficiency and does not cause permanent magnets to be damaged or scattered during high-speed rotation.

In order to achieve the above object, the rotor of the brushless motor of the present invention is an improvement to the rotor of the brushless motor with permanent magnets. The yoke is formed by stacked multilayer silicon steel sheets, and at least 4 even numbers are formed on the outer peripheral surface of the yoke. On these magnetic poles, every other magnetic pole is provided with the required grooves for arranging the permanent magnets for the magnetic field, so that the distances between the grooves and the center are approximately equal, and the surface facing the rotary shaft side has the same magnetic pole.

By referring to the description of the embodiments of the present invention with reference to the accompanying drawings, the characteristics, purpose and effects of the present invention can be further understood.

Example

First, a first embodiment will be described with reference to FIGS. 1 to 4 .

Fig. 1 shows a brushless motor with a permanent magnet rotor according to the present invention, with 20 representing its overall brushless motor having a motor casing (stator) 2 that surrounds it, and this motor casing 2 is made of a cylindrical shape The side wall 3 is composed of a front panel 4 and a rear panel 5, and a plurality of excitation coils 6 arranged in a cylindrical shape are fixed on the inner side wall surface of the side wall 3. The rotary shaft 8 is concentrically fixed at the center of the rotor 7 . The rotary shaft 8 protrudes from both ends of the rotor 7, one end of which is rotatably supported in a bearing 10 mounted on the rear panel 5 of the motor housing 2, and the other end is rotatably supported in a bearing 10 mounted on the motor body. 2 in the bearing 12 on the front panel 4. A support structure 13 for an annular magnetic pole sensor is provided inside the side wall 3 of the motor housing 2, and a plurality of magnetic pole sensors 14 are mounted and held on the support member 13 and positioned near the surface of the rotor 7.

In this brushless motor 20, the magnetic pole position of the rotor 7 is detected by the above-mentioned magnetic pole sensor 14, the current is passed through the corresponding excitation coil 6 by a control circuit not shown in the figure, and the rotor 7 is rotated by the interaction between the current and the magnetic force lines. . The magnetic pole position of the rotated rotor 7 is detected by the magnetic pole sensor 14 again, and the current is supplied to different excitation coils 6 by the above-mentioned control circuit, and the rotor 7 is driven to rotate again. By repeating the above operation, the rotor is continuously rotated, and this rotational force is taken out as power through the rotary shaft 8 to the outside of the motor.

FIG. 2 shows the rotor 7 of this embodiment, and FIG. 3 shows the silicon steel sheet 22 constituting the rotor 7. As shown in FIG. The yoke 21 of the rotor 7 is integrated by laminating a plurality of silicon steel sheets 22 along the axial direction of the rotary shaft 8 and pressing them into a rectangular caulking 23 formed by molding.

The silicon steel sheet 22 is made of a material with high magnetic permeability, and an inorganic insulating coating film with a thickness of 0.35 mm or 0.5 mm is formed on its surface. As shown in FIG. 1. Its top becomes arc-shaped magnetic poles 24a, 24b, on 2 magnetic poles 24a facing each other in these magnetic poles, a pair of slots 25 for inserting permanent magnets 30 and 31 are arranged symmetrically relative to the center of rotation. By providing the above-mentioned groove 25 in the magnetic pole 24a, the top end and the base of the magnetic pole 24a are connected by bridges 26 at both ends of the groove. In addition, a rotary shaft opening 27 for inserting the rotary shaft 8 is provided at the center of the silicon steel sheet 22 , and a key groove 28 is provided around the rotary shaft opening 27 .

The rotary shaft 8 is formed so that the central portion expands outward, and has a shape capable of being fitted with the rotary shaft opening 27 without a gap. After the silicon steel sheets 22 are laminated to form the yoke 21 , the rotary shaft 8 is inserted into the rotary shaft opening 27 . A key 29 is provided at the expanded central portion of the rotary shaft 8, and the key engages with the above-mentioned key groove 28 so that the rotor 7 cannot rotate relative to the rotary shaft 8 individually.

In this embodiment, the yoke 21 is formed by stacking silicon steel sheets 22 , but cold-pressed steel (SPCC steel) may also be used instead of the silicon steel sheets 22 to form the yoke 21 .

The above-mentioned yoke 21 is constituted by inserting a pair of permanent magnets 30, 31 into the groove 25 so that their N poles face each other. Therefore, the permanent magnets 30 and 31 are sandwiched in the radial direction by the silicon steel sheet 22 made of a high magnetic permeability material. And, by the mutual repulsion of the N poles of the permanent magnets 30, 31, the magnetic plate 24a is provided with the S polarity, and the 24b is provided with the N pole polarity, and the whole rotor 7 becomes a rotor structure with 4 poles.

FIG. 4 shows the flow of magnetic lines of force of the rotor 7 when the rotor 7 is positioned inside the brushless motor 20 . The magnetic lines of force coming out from the N pole of the permanent magnet 30 pass through the bridge 26 to reach the S pole, and then because the width of the bridge 26 is set to be very narrow, the density of the magnetic line of force in it is easy to reach saturation. Between adjacent S poles 24a and N poles 24b, a notch 24' is provided. Due to the mutual repulsion of the permanent magnets 30, 31 facing each other with the same polarity, the lines of magnetic force flow from the magnetic poles 24b as shown in FIG. The magnetic pole surface of the magnetic pole 24a comes out, passes through the inside of the exciting coil 6, and reaches the S pole through the magnetic pole surface of the magnetic pole 24a. The crimping portion 23 is formed into a rectangle, and the long side is inclined at 45° with respect to the magnetic direction of the rotor 7 so as not to interfere with the lines of magnetic force.

In this way, in this embodiment, by setting a plurality of magnetic poles protruding radially along the silicon steel sheet, a groove is provided on each magnetic pole, and a permanent magnet with the same pole facing each other relative to the center of rotation is inserted in the groove, and the gap between the magnetic poles is utilized. The same poles repel each other, and a rotor with twice the number of magnetic poles equivalent to the number of permanent magnets can be obtained.

In addition, since the permanent magnets are inserted into the slots, and are clamped by high magnetic permeability materials along the radial direction, there is no scattering caused by high-speed rotation, and therefore, there is no need to wrap the outer circumference of the rotor to prevent scattering. , while the iron loss caused by the scattering preventing member does not exist, and since the yoke is composed of laminated steel plates, the iron loss can be kept to a minimum.

In addition, since the permanent magnet of this embodiment is formed into a simple shape, high-precision surface processing is not required, so the processing is simple, making the permanent magnet extremely easy to manufacture.

Next, a second embodiment will be described with reference to FIG. 5 .

In FIG. 5 , since a part of the magnetic force lines coming out from the N pole of the permanent magnet 30 does not return to the S pole through the magnetic pole surface of the magnetic pole 24 b due to so-called magnetic leakage, the width W of the magnetic pole surface of the magnetic pole 24 a _{is 1} When it is equal to the magnetic pole surface width _W2 of the magnetic pole 24b, the total magnetic flux of the magnetic pole surface of the magnetic pole 24a is larger than the total magnetic flux of the magnetic pole 24b. Therefore, in this embodiment, the total magnetic flux on the magnetic pole surfaces of the magnetic poles 24a and 24b is made the same by increasing the magnetic pole surface width _W2 of the magnetic pole 24b, whereby the generated torque can be made uniform.

Furthermore, a third embodiment will be described with reference to FIGS. 6 and 7 .

In this embodiment, as shown in FIG. 6, grooves 33 are provided in the magnetic poles 24a, 24b in the same direction as the respective magnetic directions. Since it generally has the property that the magnetic force lines coming out from the N pole reach the S pole through the shortest distance, when comparing with Fig. 4 of the above-mentioned embodiment, the magnetic flux density at the end of the magnetic pole surface of the magnetic pole 24a is lower than that at the center. In this regard, by providing grooves 33 on the magnetic poles, the lines of magnetic force can be forcibly guided so that they can enter and exit from the magnetic pole faces along the grooves 33.

Fig. 7 shows the flow of magnetic lines of force in this embodiment, so that the lines of magnetic force coming out from the N pole of the permanent magnet 30 are guided in the slot 33, pass through the excitation coil 6, and return to the S pole of the permanent magnet 30 while being guided in the slot 33 of the magnetic pole 24a . The action of the magnetic flux fixing groove 33 makes the magnetic flux evenly distributed on the same magnetic pole surface, so that the generated torque is also uniform, so that the heat distribution of the permanent magnet rotor is improved, and the advantage of increasing the cooling area can be obtained.

Next, a fourth embodiment will be described with reference to FIG. 8 .

FIG. 8 shows a section through a six-pole rotor 7 . In this embodiment, the magnetic poles 24a, 24b, 24c are formed at an angle of 60° to each other and protrude radially, and permanent magnets 34a, 34b, 34c. The center of the yoke 21 is provided with a rotary shaft opening 27 into which the rotary shaft can be inserted, and a key groove 28 is provided in the rotary shaft opening 27 to prevent the rotary shaft from rotating relative to the rotor.

Since each permanent magnet 34a, 34b, 34c of this embodiment is arranged so that the respective N poles face inwardly, the magnetic lines of force from one N pole, as shown in the figure, are repelled by the N poles of other permanent magnets. , to reach the S pole through the adjacent magnetic pole surface. According to this, the magnetic pole having the permanent magnet has the S pole, and the magnetic pole not including the permanent magnet has the magnetic force in the N pole.

In this embodiment, the permanent magnets are cast magnets made of praseodymium (Pr) alloys. However, cast magnets (Alnico magnets, praseodymium magnets), sintered magnets (ferrite magnets, rare earth magnets), and resin bonded magnets can also be used. (Ferrite magnets, rare earth magnets) any kind of magnet.

In addition, the permanent magnet is rolled into a plate shape with a rectangular cross section, and the length of the side corresponding to the direction of the rotor axis is 2 to 5 times the length of the side close to the rotation direction of the rotor. Since it is formed into a plate shape with a rectangular cross section, it is easier to process than conventional tile-shaped magnets. In addition, since it does not need to be attached to the outer periphery of the yoke, it can save precise surface processing. In addition, since the permanent magnets are inserted into the grooves 25 and clamped in the radial direction by high magnetic permeability materials, the magnets will not be scattered due to the rotational force, and can be used in high-speed rotary motors.

In addition, since the silicon steel sheet 22 for the yoke 21 of the present invention is formed by press forming, productivity is high, and since a rotor with a precise outer diameter can be obtained, a high-efficiency motor can be produced.

Hereinafter, a fifth embodiment will be described.

In this embodiment, the bridge 26 is provided with a groove to limit the passage of magnetic flux.

That is, in FIG. 9 in which a part of the magnetic pole 24a is enlarged, a part of the magnetic flux coming out from the N pole of the magnetic field permanent magnet 30 reaches the S pole of the permanent magnet 30 through the bridge 26 as shown in the figure. Since the magnetic flux passing through the bridge 26 does not pass through the outer space of the yoke 21 and does not intersect with the stator of the motor, there is no force to drive the rotor in rotation. By reducing the magnetic flux through this bridge 26, the magnetic force of the permanent magnets 30 can be used more efficiently.

The magnetic flux φ passing through the above-mentioned bridge 26 can be calculated by the following equation. When the cross-sectional area of the bridge 26 is defined as S, the magnetic flux density of the silicon steel sheet 22 is defined as B, the relationship

φ=B×S

established. It can be seen from the formula that if the magnetic flux passing through the bridge 26 is to be reduced, the cross-sectional area of the bridge 26 should be reduced.

In this embodiment, the bridge 26 is provided with grooves for limiting magnetic use. The cross-sectional area of a part of the bridge 26 forming the groove 26a is reduced. The magnetic flux through bridge 26 can be limited with this small cross-sectional area.

By respectively providing the above-mentioned magnetically limiting grooves 26a on the bridges 26, 26, the magnetic flux passing through the bridges 26, 26 can be limited, and the magnetic force of the permanent magnets for the magnetic field can be more effectively used to obtain a more effective permanent magnet rotor.

In forming the above-mentioned limiting magnetic common groove 26a, at first, each silicon steel sheet 22 is formed by drawing, and then, the silicon steel sheet 22 is stacked to form the yoke 21, and the bridge 26 of the formed yoke 21 is formed by grinding equipment, etc. 26 is formed with grooves 26a, 26a. Compared with the deposition process of the silicon steel sheet 22, the processing for forming the grooves 26a, 26a is easier to control with high dimensional accuracy, and the bridges 26, 26 can be formed with extremely small sections. Accordingly, the permanent magnet rotor of the present invention is easier to manufacture than a permanent magnet rotor having no grooves in the bridge portion, and can have a bridge portion with a very small cross-sectional area.

Next, a sixth embodiment will be described.

In this embodiment, the above-mentioned bridge 26 is provided only on one side of the groove 25, and the bridge 26 is made to exist on one side in the rotation direction.

Just as shown in Figure 10, the groove 25 is a semi-closed type, that is, the bridge 26 connecting the side part 26b of the magnetic pole and the magnetic pole base is a single support, and its shape is point-symmetrical with respect to the center of rotation. Bridge 26, there is no bridge on the reverse rotation direction side.

The permanent magnets 30, 31 are inserted axially into the groove 25 of the yoke 21 formed by stacking silicon steel sheets. As shown in Figure 10, on the side that does not establish the bridge of silicon steel sheet, set stopper 26c, because it plays stopper effect after inserting permanent magnet 30,31, also can not take place magnet flying phenomenon even when turning around.

Figure 11 shows the magnetic force lines when a load torque acts according to the magnetic field analysis. The width of the bridge 26 is the width through which the leakage magnetic flux passes, and the thickness is the thickness through which the leakage magnetic flux occurs at both ends of the permanent magnet 30 .

Therefore, leakage magnetic flux occurs in the bridge 26 as shown in Fig. 11, and magnetic flux saturation occurs in the bridge and its vicinity on the magnetic pole side. Therefore, even when a load current flows, the magnetic flux from the permanent magnets 30, 31 is less likely to bend at the one side portion 26b of the magnetic pole. Therefore, the center of the magnetic pole on the outer circumference of the rotor is less likely to move due to load, and it is easy to introduce sensorless technology. In addition, since there is no leakage magnetic flux on the side where no bridge is provided, the magnetic flux from the center of one side of the magnetic pole is increased to the left. Therefore, even if there is leakage magnetic flux at the bridge, it will not affect the total magnetic flux. will reduce a lot.

Next, a seventh embodiment will be described.

In this embodiment, the ends 30a, 31a of the permanent magnets 30, 31 facing the side of the bridge 26, and the ends 30b, 31b along the axial direction of the permanent magnets are covered with non-magnetic materials.

Just as shown in FIG. 12, the spacer 32 made of aluminum or non-magnetic stainless steel is formed into a frame capable of covering both ends of the permanent magnets 30, 31 and both ends along their axial direction. The size of the frame is exactly the size that can put the permanent magnet therein. In order to prevent the magnet from being exposed when the magnet is put in, the height of the frame should be made smaller than the thickness of the magnet.

When assembling, the permanent magnets 30 and 31 are inserted into the separator 32 along the magnetization direction to be integrated, and then inserted into the groove 25 of the yoke 21 . Fig. 13 is a sectional view showing the assembly.

In addition, Fig. 14 shows the direction of the magnetic flux after it is installed in the magnetic circuit. As shown in the figure, since there are non-magnetic partitions 32 at both ends of the permanent magnet 30, it is difficult for the magnetic flux to flow there, so that the magnetic flux from the magnet hardly leaks, thereby reducing the leakage magnetic flux. The effective magnetic flux leaked from the gap can not be missed.

Moreover, since the permanent magnet is not exposed from the spacer, when the magnet and the spacer are inserted, the magnet does not come into contact with the groove of the yoke. As a result, the surface of the magnet is not damaged and there is no need to worry about rust.

Next, an eighth embodiment will be described.

In this embodiment, as shown in FIG. 16 , a through-hole 15 for a rotary shaft having a diameter larger than the outer diameter of the rotary shaft 8 is formed in the above-mentioned yoke 21 , and the above-mentioned rotary shaft 8 is arranged approximately concentrically in the through-hole 15 for a rotary shaft. Inside, a member 16 for preventing magnetic flux leakage is formed between the outer peripheral surface of the rotating shaft 8 and the through hole 15 for the rotating shaft of the yoke 21, and the yoke 21 and the rotating shaft 8 are fixed and formed by the member 16 for preventing magnetic flux leakage. One.

Exactly a kind of brushless motor of the present invention is shown in Figure 15, and the magnetic flux of rotor 7 passes through the outer space of permanent magnet rotor 7 because of the mutual repulsion of the same magnetic poles of permanent magnets 30 and 31 for the magnetic field, and as shown in the figure And intersect with the stator core 17 . The magnetic poles of the stator core 17 generate a rotating magnetic field by the current flowing through the exciting coil 6 . The permanent magnet rotor 7 is driven to rotate by the rotating magnetic field of the magnetic poles of the stator core 17 described above.

In addition, the above-mentioned permanent magnet rotor 7 is formed in the central portion of the yoke 21 with a through hole for the rotary shaft whose inner diameter is approximately equal to the diameter of the rotary shaft 8. When the permanent magnet rotor 7 is assembled, the yoke 21 is heated to make the above-mentioned After the through hole is heated and expanded for the rotary shaft, the rotary shaft 8 is pressed into it. When the yoke 21 is cooled after being pressed in, the through hole for the rotating shaft of the yoke 21 and the outer peripheral surface of the rotating shaft 8 can be closely bonded, so that the yoke 21 and the rotating shaft 8 are integrated.

When assembling the permanent magnet rotor having balance weights on both ends of the yoke 21, after manufacturing the balance weight in a separate process, press the rotating shaft through the through hole of the balance weight and the yoke as described above.

In the above-mentioned permanent magnet rotor of the brushless motor developed by the applicant, there is still concern that part of the magnetic flux leaks through the inside of the rotating shaft to the outside of the end surface of the permanent magnet rotor in the axial direction. If a part of the magnetic flux leaks, since this part of the magnetic flux does not interlink with the defined iron core, the magnetic force of the permanent magnet cannot effectively have a beneficial effect on the rotation of the motor, which may reduce the efficiency of the brushless motor.

Therefore, an object of the eighth embodiment is to provide a permanent magnet rotor which can substantially prevent leakage of magnetic flux to the outside of the axial end surface of the rotor and is easy to manufacture for the permanent magnet rotor of the brushless motor developed by the above-mentioned applicant.

That is, as shown in FIG. 16, the center portion of the permanent magnet rotor 7 has a through hole 15 for the rotary shaft, and a magnetic flux leakage prevention member 16 made of aluminum die-casting material is provided between the yoke 21 and the rotary shaft 8. Further, Balance weights 18 made of die-cast aluminum are provided on both end surfaces of the yoke 21 . Since the aluminum die-casting material has a property of blocking magnetic flux, the magnetic flux does not pass through the magnetic flux leakage prevention member 16 and the balance weight 18 . For this reason, at both ends of the permanent magnets for the magnetic field, the magnetic flux flowing to the outside of the two ends of the yoke 21 through the inside of the rotary shaft 8 is blocked by the magnetic flux leakage prevention member 16 and the balance weight 18, and does not extend to the yoke. 21 outside the two ends.

When the permanent magnet rotor 7 is used in a brushless motor, as shown in FIG. Make current flow through the excitation coil 6 of the brushless motor to generate a rotating magnetic field on the magnetic poles of the stator discus 17, and use the interaction between the rotating magnetic field of the stator core and the magnetic force lines of the permanent magnet rotor to rotate and drive the rotor of the permanent magnet. There are many magnetic force lines interlinked with the stator core, which can make the rotation torsion larger. Therefore, if the permanent magnet rotor 7 of the present embodiment is adopted, the lines of force of the permanent magnets 30 and 31 for the magnetic field do not protrude to the outside of the two end faces of the yoke 21, but all interlink with the stator core 17, thereby effectively Use its magnetic field lines to generate rotational force.

In addition, since the permanent magnet rotor 7 of this embodiment slowly inserts the rotary shaft 8 into the through hole 15 for the rotary shaft, the magnetic flux leakage prevention member 16 and the counterweight 18 are integrally formed with cast aluminum, Process Manufacture of the balance weight can save the process of assembling it together with the yoke to the permanent magnet rotor. According to this, the manufacture of the permanent magnet rotor can be facilitated.

In the above-mentioned embodiment, the permanent magnet rotor with the balance weight is used for explanation. However, even for the permanent magnet rotor using only the magnetic flux leakage prevention member, since the magnetic flux leakage prevention member blocks the magnetic flux passing through the rotary shaft, Therefore, the motor efficiency can be improved.

In addition, the fabrication of the magnetic flux leakage prevention member is not limited to the use of cast aluminum, and the same effect can also be obtained by using materials with low magnetic permeability, such as resin.

Next, a ninth embodiment will be described.

In this embodiment, protrusions engaged with the magnetic field permanent magnets 30, 31 pressed into the groove 25 are provided on the inner peripheral surface of the yoke 21 forming the groove 25 described above.

That is, as shown in FIG. 18 and FIG. 19 , a plurality of ribs 36 are provided on the inner peripheral surface of the silicon steel sheet 22 forming the grooves 25 and 25 , so that the two sides of the triangles of these ribs protrude into the groove 25 .

The magnetic field permanent magnets 30, 31 are held inside the groove 25 by engaging part of their surface with the tip of the rib 36 when they are pressed in, as shown in the figure. Utilize this rib 36 to make the permanent magnets 30, 31 and the inner peripheral surface of the groove 25 not form surface contact, therefore, when the permanent magnets 30, 31 are pressed into the inside of the groove 25, the contact between the permanent magnets 30, 31 and the groove 25 The generated frictional force is small, and it can be pressed with a small force.

In addition, after press-fitting, as shown in the figure, since the tips of the ribs on the outer peripheral surface of the permanent magnet are joined, the permanent magnet does not come off. The permanent magnet rotor 7 of this embodiment does not use an adhesive to keep the permanent magnets 30, 31 inside the groove 25, so when it is used inside the refrigerant or pressurized fluid, it will not be dissolved in the refrigerant or pressurized by the adhesive. The permanent magnet falls off due to the fluid pressure.

As shown in FIG. 20, on the inner peripheral edge portion of the silicon steel sheet 22 forming the groove 25, there is provided a grooved portion 23 necessary for stacking the silicon steel sheet 22 integrally. A part of the silicon steel sheet is dented with a metal molding press to form the above-mentioned crimped groove. By providing this crimping groove on the peripheral edge of the silicon steel sheet, the peripheral edge of the silicon steel sheet is deformed by the pressure of the metal mold, protruding into the groove 25 as shown in the figure to form a rib 36 . Thus, by forming the ribs 36, part of the rib forming process can be omitted, and the permanent magnet rotor 7 which can be manufactured more easily can be obtained.

Fig. 21 shows a part of a yoke as another example of the permanent magnet rotor of this embodiment.

In this example, the rib 36 of the silicon steel sheet 22 is a triangular-shaped joint 37 with a permanent magnet joint with a magnetic field not shown in the figure, and a notch formed on both sides of the triangle base of this joint 37 38 compositions. The triangular base of the junction 37 is provided on the inner side of the yoke than the inner peripheral edge portion of the silicon steel sheet 22 forming the groove 25 . The joint portion 37 is connected to the inner peripheral edge portion of the silicon steel sheet forming the groove 25 through the notch portion 38 .

In order to engage with the permanent magnet for the magnetic field, it is necessary for the protrusion of the rib to have an apex angle within a predetermined angle and a predetermined height. When the protrusion angle of this rib is made too large, it is necessary to press in the permanent magnet for the magnetic field with a large force. In addition, when the ribs do not have a predetermined height, the ribs are deformed by pressing in the permanent magnets for the magnetic field, so that the ribs cannot function as they should. But so-called on the periphery of the silicon steel sheet that forms groove, be provided with the rib of apex angle and height of above-mentioned condition, just equal to make the sectional area of the permanent magnet that can be pressed into the magnetic field in the groove small, or make the opening of the groove large, This is contrary to the miniaturization and high efficiency requirements of the brushless motor.

Since the rib 36 has the above-mentioned engaging portion 37 and the notch portion 38, the opening of the groove 25 is not enlarged, or the cross-sectional area of the permanent magnet for the magnetic field is not reduced, so that the permanent magnet is easily pressed in and pressed in. Finally, it can be effectively engaged with the permanent magnet to prevent the permanent magnet from falling off.

In addition, above, the protruding part which engages with the permanent magnet for a magnetic field has been described as having a triangular edge, but the shape of the protruding part is not limited thereto. For example, a semicircular protruding part with a small diameter may be formed at the tip.

In addition, as the yoke, it is not limited to laminated silicon steel sheets, but can also be made of an integral metal material, with a slot for pressing a permanent magnet for a magnetic field inside, and then formed on the inner peripheral surface of the slot to engage with the permanent magnet for a magnetic field. of the protrusion.

Next, a tenth embodiment will be described.

In this embodiment, the magnetic field permanent magnets 30, 31 shorter than the axial length of the yoke 21 are inserted into the above-mentioned groove 25, and the center of gravity of the object to be rotated is eccentric in the cavity of the above-mentioned groove after the magnetic field permanent magnet is inserted. Move and fill putty and other materials, because the above-mentioned putty and other materials form a balance weight after curing.

That is, FIG. 22 shows a permanent magnet rotor 7 provided with a balance weight. This permanent magnet rotor 7, since the length of the permanent magnets 30 and 31 for the magnetic field are formed to be shorter than the axial length of the yoke 21, the yoke There is a cavity in the groove 25 of 21 . As shown in the figure, the cavity is filled with a putty material mixed with metal fine particles and resin, and the putty material is solidified to form a balance weight 39 .

Like this, because in the interior of the yoke iron 21 of the permanent magnet rotor 7, the balance weights 39, 39 are respectively arranged on different sides of the permanent magnets 30, 31 for the magnetic field, so the positions of the center of gravity of the yoke iron 21 are respectively on the opposite side of the yoke iron 21. The two ends of 21 are offset to prevent the resonance of the entire system composed of the rotary shaft and the above-mentioned eccentric rotor, thereby absorbing the vibration of the eccentric rotor caused by the rotation.

In Fig. 22, the weights of the counterweights 39, 39 are adjusted for the above purpose. That is, in order to eliminate the oscillation resonance of the entire system composed of the rotary shaft and the above-mentioned eccentric rotor, the ratio of the putty to the metal particles of the resin is adjusted, and then it is filled into the cavity of the groove 25 . Or adjust the amount of putty material to form balance weights 39 of different sizes. In addition, aluminum castings other than putty materials composed of metal particles and resin may be used as the above-mentioned putty material.

As mentioned above, since the balance weight of the permanent magnet rotor in this embodiment is set inside the yoke, there is no protruding portion of the balance weight on the outer surface of the yoke, and there is no protruding portion of the balance weight to receive the fluid during rotation. The problem of resistance. Furthermore, since the balance weight is installed inside the yoke, there is no problem that the balance weight is scattered due to the centrifugal force generated by the rotation of the permanent magnet. According to this, a permanent magnet rotor with high rotary driving efficiency and which can completely prevent the accident of flying of the counterweight can be obtained.

Hereinafter, an eleventh embodiment will be described.

This embodiment is an additional cooling structure on the rotor.

That is, in FIG. 23 , heat pipes 19 , 19 are embedded in the yoke 21 so as to be in contact with the above-mentioned permanent magnets 30 , 31 . The heat pipe 19 is filled with an operating liquid, and the operating liquid is used for heat exchange. Specifically, the heat pipe 19 that receives the internal heat of the yoke from the heat receiving part inserted into the yoke 21 exchanges heat with the outside air through the heat radiation part protruding from the yoke, and then returns the working fluid to the heat receiving part again. In this way, the heat pipe 19 continuously releases the internal heat of the permanent magnet or the yoke iron to the outside, so that the permanent magnet is cooled.

24 and 25 show that the rotary shaft 8 is used as the heat pipe axis. In such a configuration, a fully enclosed permanent magnet rotor capable of releasing heat to the outside can be formed. In addition, in this embodiment, the yoke can be made of sintered alloy, bulk iron, or cold-rolled steel (SPCC material).

Hereinafter, the rotor manufacturing method according to the present invention will be described in detail.

As can be seen from the above description, the permanent magnet rotor of the present invention forms a yoke with a slot for inserting a permanent magnet for a magnetic field on the one hand, and forms a permanent magnet for a magnetic field matching the shape of the slot of the yoke on the one hand, and then the above-mentioned The magnetic field is produced by pressing permanent magnets into slots in the yoke.

That is, in manufacturing the permanent magnet rotor 7, the yoke 21 and the permanent magnets 30, 31 for the magnetic field are manufactured separately, and the manufactured permanent magnets for the magnetic field are inserted into the inside of the yoke to form the permanent magnet rotor 7. The yoke 21 is formed by laminating a plurality of silicon steel sheets 22 . Magnetic poles 24 (24a, 24b, 24c) are formed on each silicon steel sheet 22 and the outer periphery, and openings through which permanent magnets for magnetic fields pass are formed inside the magnetic poles by forming dies. Furthermore, on each silicon steel sheet 22, a rectangular depressed groove portion 23 is formed by molding.

The yoke 21 is formed by pressing the grooved portions 23 of the respective silicon steel sheets 22 into each other to join the silicon steel sheets 22 into one body. The openings of the silicon steel sheets 22 are overlapped to form grooves 25 for inserting the permanent magnets 30 and 31 for the magnetic field.

On the other hand, as for the permanent magnet for magnetic field, firstly, a powdery magnetic body and an epoxy resin binder are kneaded together, put into a mold, and formed into a predetermined shape in a magnetic field. The formed magnetic field permanent magnets are hardened by heat treatment, and the surface is cut to conform to the shape of the groove 25 of the yoke 21 to form the magnetic field permanent magnets 30, 31 for assembly.

The permanent magnet for the magnetic field is pressed into the groove 25 of the yoke 21, and the permanent magnet rotor 7 is manufactured.

Next, another manufacturing method for the permanent magnet rotor of the brushless motor that can manufacture the permanent magnets for the magnetic field and the permanent magnet rotor with complex shapes, and does not damage the permanent magnets for the magnetic field when the permanent magnet rotor is assembled. Be explained.

The production method is to set a groove for placing a permanent magnet for the magnetic field inside the yoke of the permanent magnet rotor of the brushless motor, and mix the pulverized powdery magnetic body and epoxy resin binder to fill it into the groove, so that It is in the magnetic field applied in the radial direction relative to the rotation axis of the permanent magnet rotor. The above-mentioned powdery magnetic body and epoxy resin binder are compressed, and after compression molding, thermal hardening treatment is performed, and directly in the groove of the yoke Permanent magnets are used to form a magnetic field.

FIG. 23 shows a step of forming a permanent magnet for a magnetic field in the groove 25. As shown in FIG. The yoke 21 is arranged on a base 42 having a coil 41 as shown in the figure. A jig 40 having a compression opening 43 having the same shape as the groove 25 and a compression piston 44 is provided on the top surface of the yoke 21 . This jig 40 contains a coil 45 . Groove 25 of yoke 21 is filled with permanent magnet raw material 46 obtained by kneading powdery magnetic material and epoxy resin binder. Since the volume of the permanent magnet raw material 46 is reduced by compression, the raw material slightly larger than the volume of the groove 25 is filled in advance, and a part thereof is extruded from the compression opening 43 of the jig 40 .

The current flows through the coils 41 and 45, as shown in the figure, forming a magnetic field in which the magnetic field lines pass through the center of the yoke and interlink with the filled permanent magnet raw material 46 from the inside of the slot 25 toward the outside. Next, the compression piston 44 is forcibly moved in the direction P shown in the figure by means of hydraulic pressure or the like, and the permanent magnet raw material 46 is compressed to form a permanent magnet for a magnetic field.

After the above-mentioned compression molding, the yoke 21 is removed from the jig 40 and the base 42, and subjected to thermosetting treatment at 100°-150° C. to harden the magnetic field inside the yoke 21 with a permanent magnet.

In this way, as shown in FIG. 4 and the like, permanent magnets for the magnetic field are formed inside the slots 25 of the permanent magnet rotor 7 . Utilizing the influence of the magnetic field during compression molding, the inner side of the permanent magnet is magnetized into an S pole, and the outer side is turned into an N pole. Since the permanent magnets 30, 31 for the magnetic field are formed to face the magnetic pole faces with the same magnetic properties, as shown in the figure, the magnetic field lines come out from the magnetic pole 24a of the yoke 21 to the magnetic pole 24b by utilizing the repulsion of the same pole. The magnetic lines of force are intersected with the stator of the motor not shown in the figure, which is arranged near the outer peripheral surface of the yoke, and the permanent magnet rotor 7 is driven to rotate by interaction with the stator.

According to the manufacturing method of the permanent magnet rotor of the present embodiment as described above, since the permanent magnets for the magnetic field can be directly formed inside the yoke, the manufacture is easy, and the permanent magnets for the magnetic field will not be damaged during the process of pressing them in. In addition, a permanent magnet for a magnetic field with a complex shape can be formed inside the yoke, especially in a permanent magnet rotor in which the position of each magnetic pole of the yoke is slightly twisted in the direction of the permanent magnet rotor axis.

As shown in FIG. 24 , in the twisted permanent magnet rotor 7 , a plurality of silicon steel sheets 22 are stacked by rotating each time a small angle with respect to the rotary shaft 8 . The slots 25 of the permanent magnet rotor 7 form helical bends inside the permanent magnet rotor. Even for the slot 25 having such a complicated shape, the permanent magnets 30, 31 for the magnetic field can be directly formed inside the slot 25 by the same method as described in FIG. 23 .

In addition, in the above-mentioned embodiment, a pair of permanent magnets for the magnetic field are provided inside the yoke, and four alternating N and S poles are formed on the outer surface of the yoke by utilizing the mutual repulsion of the same magnetic poles of the permanent magnets for the magnetic field. The permanent magnet rotor with magnetic poles was described, however, the method of manufacturing the permanent magnet rotor for a brushless motor according to the present invention is not limited to the permanent magnet rotor with the above-mentioned structure. That is, for a permanent magnet rotor having any number of magnetic poles on the outer peripheral surface, or a permanent magnet rotor having magnetic field permanent magnets for each magnetic pole, the magnetic field permanent magnets can be formed directly inside the yoke similarly.

In addition, in the embodiment, a permanent magnet for a magnetic field having a rectangular cross-section is used for description, but the cross-sectional shape of the permanent magnet for a magnetic field may be any shape.

According to the above manufacturing method, a permanent magnet rotor that is easy to manufacture and highly efficient can be obtained. In addition, if this manufacturing method is adopted, the permanent magnet does not need to be cut during the manufacturing process. Furthermore, since damage to the permanent magnet does not occur during the manufacturing process, the permanent magnet can be effectively used.

In addition, since the permanent magnets for the magnetic field are directly formed in the slots of the yoke, it is also applicable to slots of complex shapes. That is, in addition to being able to easily form permanent magnets for magnetic fields with complex cross-sectional shapes, it is also possible to obtain a manufacturing method that is easy to manufacture for permanent magnet rotors in which curved grooves are formed inside the yoke.

Claims (21)

1. The rotor of a brushless motor with permanent magnets is formed by stacking multiple silicon steel sheets to form a yoke, and an even number of at least 4 magnetic poles is formed on the outer periphery of the yoke, which is characterized in that every other magnetic pole on these magnetic poles is separated from the center. Equal distances are provided as grooves for placing permanent magnets for the magnetic field, and the permanent magnets for the magnetic field are placed in the grooves so that the surface facing the side of the rotating shaft has the same magnetic properties. 2. The rotor according to claim 1, characterized in that the above-mentioned permanent magnets can be AlFeNiCo permanent magnets, praseodymium magnets, sintered ferrite magnets, sintered rare earth magnets, resin-bonded ferrite magnets And any of resin-bonded rare earth magnets. 3. The rotor according to claim 1, wherein the width of the magnetic pole surface in which the permanent magnet is inserted is set to be smaller than the width of the magnetic pole surface in which the permanent magnet is not inserted. 4. The rotor according to claim 1, characterized in that thin slits are provided on each magnetic pole to make the magnetic force lines on the magnet surface evenly distributed. 5. The rotor according to claim 1, wherein a bridge connecting the top end and the base of the magnetic pole is provided at both ends of the slot, and the width of the bridge is sufficiently small in order to saturate the magnetic flux density passing through the bridge. 6. The rotor according to claim 1, wherein grooves for restricting passage of magnetic force lines are provided on the bridges at both ends of the grooves connecting the top ends of the magnetic poles and the bases. 7. The rotor according to claim 1, wherein a bridge connecting the top end and the base of the magnetic pole is provided only on one side of the slot, and the bridge exists on one side in the direction of rotation. 8. The rotor according to claim 7, wherein the width of the bridge is set to allow a leakage magnetic flux to flow, and the width of the permanent magnet is set to be thick enough to generate a leakage magnetic flux at both ends. 9. The rotor according to claim 1, wherein the end of the permanent magnet facing the side of the bridge and the two ends of the permanent magnet in the axial direction are covered with a non-magnetic material. 10. The rotor according to claim 1, wherein said yoke has a through hole for a rotary shaft having a diameter larger than the outer diameter of said rotary shaft, and said rotary shaft is concentrically arranged in said through hole for rotary shaft, Between the outer peripheral surface of the above-mentioned rotary shaft and the through hole for the rotary shaft of the above-mentioned yoke, a common member for preventing magnetic leakage is provided, and the yoke and the rotary shaft are integrally fixed by the common member for preventing magnetic leakage. 11. The rotor according to claim 10, wherein a balance weight is provided at both ends of said yoke, and said balance weight is integrally formed with said leakage flux preventing member by cast aluminum. 12. The rotor according to claim 10, wherein said leakage flux preventing member is made of resin. 13. The rotor according to claim 1, wherein protrusions engaging with said permanent magnets pressed into said grooves are formed on the inner peripheral surface of said yoke forming said grooves. 14. The rotor according to claim 13, characterized in that a sunken portion is formed on each of the stacked silicon steel sheets, so that the sunken portion on one silicon steel sheet fits with the sunken portion of another silicon steel sheet Therefore, the lamination groove portion integrally stacked is deformed by the groove portion provided close to the groove, and the protruding portion is formed on the peripheral edge portion of the silicon steel sheet. 15. The rotor according to claim 13, wherein the protruding portion has a triangular engaging portion that engages with the permanent magnet, and the triangular base of the engaging portion is disposed further than the inner peripheral surface of the yoke forming the groove. In the inside of the yoke facing inward, the two sides of the triangle of the joint part are connected to the inner peripheral surface of the yoke forming the groove through the notch for ensuring the protruding height of the joint part. 16. The rotor according to claim 1, characterized in that a permanent magnet shorter than the axial length of the yoke is inserted into the above-mentioned groove, and in the cavity of the above-mentioned groove after the permanent magnet is inserted, according to the rotation of the driven body The center of gravity is shifted and filled with putty material, and the solidified putty material is used to form a balance weight. 17. The rotor according to claim 1, wherein a heat pipe is embedded in said yoke so as to be in contact with said permanent magnet. 18. The rotor according to claim 1, wherein said rotating shaft is used as a heat pipe shaft. 19. A method for manufacturing a brushless motor rotor, forming a groove for disposing a permanent magnet for a magnetic field in the yoke of a brushless motor rotor having a permanent magnet, and is characterized in that the pulverized powdery magnetic substance and ring are filled in the groove The material mixed with the epoxy resin binder phase, under the condition of forming a magnetic field that is roughly radial to the rotation axis of the permanent magnet, compresses the above-mentioned powdery magnetic body and the epoxy resin binder, and passes through the compression molding. Thermal hardening process directly forms permanent magnets for magnetic fields in the grooves of the yoke. 20. A method for manufacturing a rotor of a brushless motor. A silicon steel sheet having a magnetic pole portion on the outer circumference and an opening shape for a permanent magnet for penetrating a magnetic field is formed inside the magnetic pole portion by die-cutting, and multiple layers are laminated along the same axis and in the same direction. The permanent magnet yoke is formed from the silicon steel sheet that has been molded, and it is characterized in that the groove formed by the opening of the silicon steel sheet is filled with the crushed powdery magnetic body and the epoxy resin binder. The above-mentioned powdery magnetic material and epoxy resin binder are compressed in a radial magnetic field with respect to the rotation axis of the permanent magnet, and the permanent magnet for the magnetic field is directly formed in the groove of the yoke through thermosetting treatment after compression molding. 21. A method for manufacturing a rotor of a brushless motor. A silicon steel sheet having a magnetic pole on the outer periphery and an opening shape for a permanent magnet for a magnetic field inside the magnetic pole portion is formed by drawing a die, and each silicon steel sheet is pressed against the rotating shaft by a predetermined The yoke is laminated while rotating at a small angle. It is characterized in that the spiral groove formed by the opening of the silicon steel sheet is filled with the crushed powdery magnetic body and the epoxy resin binder. The material is formed relatively permanently. The rotor shaft of the magnet rotor compresses the above-mentioned powdery magnetic material and epoxy resin binder in a radial magnetic field, and through thermosetting treatment after compression molding, permanent magnets for the magnetic field are directly formed in the grooves of the yoke.

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